// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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package org.objectweb.asm.tree;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * A node that represents a stack map frame. These nodes are pseudo instruction nodes in order to be inserted in an instruction list. In fact these nodes must(*) be inserted <i>just before</i> any instruction node <b>i</b> that follows an unconditionnal branch instruction such as GOTO or THROW, that is the target of a jump instruction, or that starts an exception handler block. The stack map frame types must describe the values of the local variables and of the operand stack elements <i>just before</i> <b>i</b> is executed. <br>
 * <br>
 * (*) this is mandatory only for classes whose version is greater than or equal to {@link Opcodes#V1_6}.
 *
 * @author Eric Bruneton
 */
public class FrameNode extends AbstractInsnNode {

	/**
	 * The type of this frame. Must be {@link Opcodes#F_NEW} for expanded frames, or {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND}, {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or {@link Opcodes#F_APPEND}, {@link Opcodes#F_SAME1} for compressed frames.
	 */
	public int type;

	/**
	 * The types of the local variables of this stack map frame. Elements of this list can be Integer, String or LabelNode objects (for primitive, reference and uninitialized types respectively - see {@link MethodVisitor}).
	 */
	public List<Object> local;

	/**
	 * The types of the operand stack elements of this stack map frame. Elements of this list can be Integer, String or LabelNode objects (for primitive, reference and uninitialized types respectively - see {@link MethodVisitor}).
	 */
	public List<Object> stack;

	private FrameNode() {
		super(-1);
	}

	/**
	 * Constructs a new {@link FrameNode}.
	 *
	 * @param type
	 *          the type of this frame. Must be {@link Opcodes#F_NEW} for expanded frames, or {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND}, {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or {@link Opcodes#F_APPEND}, {@link Opcodes#F_SAME1} for compressed frames.
	 * @param numLocal
	 *          number of local variables of this stack map frame.
	 * @param local
	 *          the types of the local variables of this stack map frame. Elements of this list can be Integer, String or LabelNode objects (for primitive, reference and uninitialized types respectively - see {@link MethodVisitor}).
	 * @param numStack
	 *          number of operand stack elements of this stack map frame.
	 * @param stack
	 *          the types of the operand stack elements of this stack map frame. Elements of this list can be Integer, String or LabelNode objects (for primitive, reference and uninitialized types respectively - see {@link MethodVisitor}).
	 */
	public FrameNode(final int type, final int numLocal, final Object[] local, final int numStack, final Object[] stack) {
		super(-1);
		this.type = type;
		switch (type) {
		case Opcodes.F_NEW:
		case Opcodes.F_FULL:
			this.local = Util.asArrayList(numLocal, local);
			this.stack = Util.asArrayList(numStack, stack);
			break;
		case Opcodes.F_APPEND:
			this.local = Util.asArrayList(numLocal, local);
			break;
		case Opcodes.F_CHOP:
			this.local = Util.asArrayList(numLocal);
			break;
		case Opcodes.F_SAME:
			break;
		case Opcodes.F_SAME1:
			this.stack = Util.asArrayList(1, stack);
			break;
		default:
			throw new IllegalArgumentException();
		}
	}

	@Override
	public int getType() {
		return FRAME;
	}

	@Override
	public void accept(final MethodVisitor methodVisitor) {
		switch (type) {
		case Opcodes.F_NEW:
		case Opcodes.F_FULL:
			methodVisitor.visitFrame(type, local.size(), asArray(local), stack.size(), asArray(stack));
			break;
		case Opcodes.F_APPEND:
			methodVisitor.visitFrame(type, local.size(), asArray(local), 0, null);
			break;
		case Opcodes.F_CHOP:
			methodVisitor.visitFrame(type, local.size(), null, 0, null);
			break;
		case Opcodes.F_SAME:
			methodVisitor.visitFrame(type, 0, null, 0, null);
			break;
		case Opcodes.F_SAME1:
			methodVisitor.visitFrame(type, 0, null, 1, asArray(stack));
			break;
		default:
			throw new IllegalArgumentException();
		}
	}

	@Override
	public AbstractInsnNode clone(final Map<LabelNode, LabelNode> clonedLabels) {
		FrameNode clone = new FrameNode();
		clone.type = type;
		if (local != null) {
			clone.local = new ArrayList<>();
			for (int i = 0, n = local.size(); i < n; ++i) {
				Object localElement = local.get(i);
				if (localElement instanceof LabelNode) {
					localElement = clonedLabels.get(localElement);
				}
				clone.local.add(localElement);
			}
		}
		if (stack != null) {
			clone.stack = new ArrayList<>();
			for (int i = 0, n = stack.size(); i < n; ++i) {
				Object stackElement = stack.get(i);
				if (stackElement instanceof LabelNode) {
					stackElement = clonedLabels.get(stackElement);
				}
				clone.stack.add(stackElement);
			}
		}
		return clone;
	}

	private static Object[] asArray(final List<Object> list) {
		Object[] array = new Object[list.size()];
		for (int i = 0, n = array.length; i < n; ++i) {
			Object o = list.get(i);
			if (o instanceof LabelNode) {
				o = ((LabelNode) o).getLabel();
			}
			array[i] = o;
		}
		return array;
	}
}
